Clinical usefulness of scintigraphy with 99mTc-galactosyl-human serum albumin for prognosis of cirrhosis of the liver

Scintigraphy with 99mTc-diethylenetriamine pentaacetic acid-galactosyl-human serum albumin (99mTc-GSA) is useful for evaluating hepatic functional reserve. We assessed the clinical usefulness of this technique, including its value in establishing a prognosis, in patients with cirrhosis of the liver.

METHODS

Scintigraphy with 99mTc-GSA was performed in 10 healthy subjects, 42 patients with chronic hepatitis and 158 patients with cirrhosis. Computer acquisition of gamma camera data were started just before the injection of 99mTc-GSA. Time-activity curves for the heart and liver were generated from regions of interest (ROIs) for the heart and the entire liver. A receptor index was calculated by dividing the radioactivity of the liver ROI by that of the liver-plus-heart ROI 15 min after the injection. An index of blood clearance was calculated by dividing the radioactivity of the heart ROI at 15 min by that of the heart ROI at 3 min.

RESULTS

The median receptor index was lower in patients with cirrhosis than in patients with chronic hepatitis or in healthy subjects, and the median index of blood clearance was higher. The receptor index was significantly lower when a complication (varices, ascites) was present. The index of blood clearance was significantly higher when a complication (varices and ascites) was present. Correlation of the two indices with classic indicators for functional reserve was significant. On the basis of the receptor index, the patients with cirrhosis were divided into two groups of roughly equal size: group A, receptor index over 0.85, and group B, receptor index 0.85 or less. On the basis of the index of blood clearance, the patients with cirrhosis were divided into two groups of roughly equal size: group A, index of blood clearance < 0.70, and group B, index of blood clearance > or = 0.70. The cumulative survival rates were lower in group B than in group A.

CONCLUSION

Scintigraphy with 99mTc-GSA is clinically useful, especially in establishing the prognosis of patients with cirrhosis of the liver.

Enhanced phosphatidylinositol 3-kinase activity and high phosphorylation state of its downstream signalling molecules mediated by ret with the MEN 2B mutation

We compared the intracellular signalling pathways through Ret tyrosine kinase activated by glial cell line-derived neurotrophic factor (GDNF), multiple endocrine neoplasia (MEN) 2A, or MEN 2B mutation. Tyrosine phosphorylation of Grb2-associated binder-1 (Gab1) and activation of phosphatidylinositol 3-kinase (PI 3-kinase) were induced at higher levels by GDNF stimulation or the MEN 2B mutation than by the MEN 2A mutation. Tyrosine-phosphorylated Gab1 was a major component that interacted with the active PI 3-kinase in vivo. In addition, we found that p62Dok and PKB/Akt were phosphorylated in a PI 3-kinase-dependent manner and the levels of their phosphorylation were significantly higher in the MEN 2B transfectant than in the MEN 2A transfectant. Tyrosine phosphorylation of p62Dok resulted in its complex formation with the Ras GTPase-activating protein (RasGAP) and the Nck adaptor protein. These findings thus suggested that high levels of activation of PI 3-kinase and of phosphorylation of its downstream signalling molecules may be associated with the clinical phenotype of MEN 2B.

Sarcomatoid carcinoma of the lung: a clinicopathologic study of 37 cases

BACKGROUND

Spindle and giant cell carcinomas of the lung are rare subtypes and are regarded as one type of lung carcinoma, termed pleomorphic carcinoma in the Armed Forces Institute of Pathology classification. This classification is different from the World Health Organization classification.

METHODS

Thirty-seven cases of sarcomatoid (spindle and/or giant cell) carcinoma of the lung were studied by light microscopy, conventional histochemistry, and immunohistochemistry to establish their clinical and histologic characteristics.

RESULTS

The patient population was comprised of 29 men and 8 women ages 33-81 years. Seventeen patients died of their disease and there was no statistically significant difference in patient prognosis between sarcomatoid carcinoma and nonsarcomatoid carcinoma of the lung. Using light microscopy, 5 cases (13.5%) comprised entirely of sarcomatoid components without carcinomatous elements were classified as Group A. In the remaining 32 cases (86. 5%), classified as Group B, carcinomatous components were present (adenocarcinoma [18 cases; 48.7%], squamous cell carcinoma [8 cases; 21.6%], and large cell carcinoma [6 cases; 16.2%]). Sarcomatoid components were divided further into three categories: spindle cell type, giant cell type, and mixed spindle and giant cell type. Immunohistochemically, the sarcomatoid components of all 37 cases were positive for cytokeratins. Statistically, there was no significant prognostic difference between the 37 cases of sarcomatoid carcinoma and 647 cases of nonsarcomatoid, nonsmall cell carcinoma of the lung (P = 0.8537).

CONCLUSIONS

The sarcomatoid portions in all sarcomatoid carcinomas in the current study showed an epithelial differentiation, and there was no apparent difference in biologic behavior between sarcomatoid carcinoma and ordinary lung carcinoma.

Characterization of the promoter region of the human RFP gene

The RFP gene encodes a Ring finger protein that has a tripartite motif consisting of a Ring finger, a B-box finger and a coiled-coil domain. In the present study, we cloned and characterized the promoter region of the human RFP gene. The nucleotide sequence of the promoter was GC-rich and had no typical TATA and CAAT boxes. Instead, it contained one AP2 and two Sp1 binding sites within 100 base pairs upstream of the transcription initiation site. Analysis by the luciferase assay revealed that the activity of this promoter region is very strong in both human and mouse cell lines, although the activity in human cells was approximately 10-15 fold higher than that in mouse cells. In addition, the AP2 and Sp1 binding sites appeared to synergistically function for the promoter activity. Thus, the promoter of the RFP gene could be useful for high levels of expression of various genes in culture cells.

Clinical need for both scintigraphy with technetium-99m GSA and per-rectal portal scintigraphy in some patients with chronic liver disease

Scintigraphy with 99mTc-diethylenetriaminepentaacetate with galactosyl human serum albumin (99mTc-GSA) and per-rectal portal scintigraphy are useful for evaluating hepatic functional reserve and portal circulation, respectively. We did the procedures simultaneously in some patients to examine the relationship between hepatic functional reserve and portal circulation in chronic liver disease. Scintigraphy with 99mTc-GSA was done in 10 healthy subjects, 45 patients with chronic hepatitis, and 165 patients with cirrhosis. Fifty-seven patients (13 with hepatitis and 44 with cirrhosis) also underwent per-rectal portal scintigraphy with 99mTc-pertechnetate within two weeks. A receptor index was calculated by dividing the radioactivity of the liver region of interest (ROI) by that of the liver-plus-heart ROI at 15 min after the injection of 99mTc-GSA. The index of blood clearance was calculated by dividing the radioactivity of the heart ROI at 15 min by that of the heart ROI at 3 min. A solution containing 99mTc-pertechnetate was instilled into the rectum, and serial scintigrams were taken while radioactivity curves for the liver and heart were recorded sequentially. A per-rectal portal shunt index was determined by calculating the ratio of counts for the liver to counts for the heart integrated for 24 seconds immediately after the appearance of the liver time-activity curve. The median receptor index was lower for more severe liver disorders, increasing in the order of chronic hepatitis, compensated cirrhosis and decompensated cirrhosis, and the median index of blood clearance was higher. The median receptor index was significantly lower when a complication (varices, ascites, or encephalopathy) was present, and the median index of blood clearance was higher. The shunt index was correlated significantly with the two other indices, but these values for some one-third of the patients disagreed in either indices. Scintigraphy with 99mTc-GSA and per-rectal portal scintigraphy with 99mTc-pertechnetate are both needed for accurate assessment of the severity of chronic liver disease before treatment-making decisions, because in some patients, results are not correlated.

[Basic examination of hepatitis C virus (HCV) core protein quantitative method and the clinical significance in during the follow-up of the patients after interferon treatment]

We evaluated the basic efficacy and clinical usefulness of "Imucheck F-HCV Ag-core(KOKUSAI)" (Ag-Core). This kit has been developed using monoclonal antibodies against hepatitis C virus (HCV) core protein. This character is different from RT-PCR assay or branched DNA assay, which have been developed for the detection of HCV-RNA. The reproducibility of Ag-Core assay was supported by vigorous mixture of reagents during the manual pretreatment of samples. The correlation between Ag-Core assay and Amplicor HCV (RT-PCR) assay was relatively good (correlation coefficient: r was 0.735 and the qualitative accordance rate was 96.6%). The change of viral load during the IFN-alpha treatment was also in good accordance between the values determined by Ag-Core and Amplicor-HCV assay. Since it is simple, cheaper and faster than the Amplicor-HCV assay. Quantitation of HCV core protein by the Ag-Core assay is useful for monitoring the therapeutic efficacy of IFN-alpha treatment.

Molecular recognition of adenophostin, a very potent Ca2+ inducer, at the D-myo-inositol 1,4,5-trisphosphate receptor

The recognition mode of adenophostin A at the D-myo-inositol 1,4, 5-trisphosphate [Ins(1,4,5)P(3)] receptor was investigated. Comparison of conformations of Ins(1,4,5)P(3) and adenophostin A by using the combination of NMR and molecular mechanics (MM) calculations demonstrated that adenophostin A adopted a moderately extended conformation regarding the distance between the 2'-phosphoryl group and the 3' ',4' '-bisphosphate motif, as suggested previously [Wilcox, R. A. et al. (1995) Mol. Pharmacol. 47, 1204-1211]. Based on the nuclear Overhauser effect (NOE) observed between 3'-H and 1' '-H and on MM calculations, the molecular shape of adenophostin A proved to be an extended form at least in solution, in contrast to Wilcox's compactly folded, preliminary hairpin model. GlcdR(2,3',4')P(3), an adenophostin analogue without adenine moiety, was found to be less potent than adenophostin A and almost equipotent to Ins(1,4,5)P(3). We propose the possibility that (i) the optimal spatial arrangement of the three phosphoryl groups and/or (ii) the interaction of the adenine moiety of adenophostin A with the putative binding site, if it exists in the vicinity of the Ins(1,4,5)P(3)-binding site, might account for the exceptional potency of adenophostin A.

Malignant peripheral nerve sheath tumour in the maxilla associated with von Recklinghausen's disease

Malignant transformation of neurofibromatosis is one of the most serious complications of von Recklinghausen's disease (VRD). The most common associated malignancy is the malignant peripheral nerve sheath tumour (MPNST). Few cases of MPNST associated with VRD in the maxillary region have been reported. This report describes a rare case of MPNST in the maxilla and the aggressive nature of MPNST associated with VRD.

Biological and biochemical properties of Ret with kinase domain mutations identified in multiple endocrine neoplasia type 2B and familial medullary thyroid carcinoma

Several mutations were identified in the kinase domain of the RET proto-oncogene in patients with multiple endocrine neoplasia (MEN) 2B, familial medullary thyroid carcinoma (FMTC) or sporadic medullary thyroid carcinoma. We introduced seven mutations (glutamic acid 768-->aspartic acid (E768D), valine 804-->leucine (V804L), alanine 883-->phenylalanine (A883F), serine 891-->alanine (S891A), methionine 918-->threonine (M918T), alanine 919-->proline (A919P) and E768D/A919P) into the short and long isoforms of RET cDNA and transfected the mutant cDNAs into NIH3T3 cells. The transforming activity of the long isoform of Ret with each mutation was much higher that that of its short isoform. Based on the levels of the transforming activity, these mutant RET genes were classified into two groups; a group with high transforming activity (A883F, M918T and E768D/A919P) and a group with low transforming activity (E768D, V804L, S891A and A919P) (designated high group and low group). Interestingly, the level of transforming activity correlated with clinical phenotypes; high group Ret with the A883F or M918T mutation and low group Ret with the E768D, V804L or S891A mutation were associated with the development of MEN 2B and FMTC, respectively. In addition, we found that substitution of phenylalanine for tyrosine 905 present in the kinase domain abolished both transforming and autophosphorylation activities of low group Ret whereas it did not affect the activities of high group Ret.

Mucosa-associated lymphoid tissue lymphoma of the duodenum forming multiple polypoid lesions: report of a case

We report herein the case of a patient found to have mucosa-associated lymphoid tissue (MALT) lymphoma of the duodenum forming multiple polypoid lesions. Endoscopic examination revealed multiple small nodules with a yellow-white, rough surface in the duodenal bulb. Histopathological and immunological findings subsequently suggested low-grade B-cell MALT lymphoma. Cytologically, MALT lymphoma is similar to multiple lymphomatous polyposis (MLP); however, this case, which involved multiple polypoid lesions, was confirmed not to be MLP.

Implication of expression of GDNF/Ret signalling components in differentiation of bone marrow haemopoietic cells

Glial cell line-derived neurotrophic factor (GDNF) and neurturin (NTN) mediate their actions through a unique multicomponent receptor system composed of Ret receptor tyrosine kinase and glycosyl-phosphatidylinositol-linked cell surface proteins (designated GFRalpha-1 and GFRalpha-2). In the present study, expression of these signalling components in the process of differentiation of haemopoietic cells was investigated. Ret was expressed at variable levels in normal and malignant cells of the myelomonocyte lineage. Immunohistochemical analysis of human and mouse tissues revealed that Ret expression was increased in intermediate mature myeloid cells such as promyelocytes and myelocytes and decreased in mature granulocytes and monocytes. Consistent with this observation, when THP-1 monocytic and HL-60 promyelocytic leukaemia cells expressing Ret were differentiated toward macrophages or granulocytes by treatment of 12-O-tetradecanoylphorbol-13-acetate (TPA) or all-trans retinoic acid (RA), Ret expression strikingly decreased during differentiation. Expression of GDNF, NTN, GFRalpha-1 and GFRalpha-2 was undetectable in THP-1 and HL-60 cells as well as in bone marrow haemopoietic cells. In contrast, bone marrow stromal cells appeared to express GDNF, GFRalpha-1 and GFRalpha-2 but not Ret. These findings suggested that the interaction between stromal cells and Ret-expressing haemopoietic cells in the bone marrow microenvironment may play a role in the differentiation of myelomonocyte-lineage cells through activation of the GDNF/Ret signalling pathway.

Rho-dependent and -independent tyrosine phosphorylation of focal adhesion kinase, paxillin and p130Cas mediated by Ret kinase

Glial cell line-derived neurotrophic factor (GDNF) signals through a unique receptor system that includes Ret receptor tyrosine kinase and a glycosyl-phosphatidylinositol-linked cell surface protein. In the present study, we have identified several proteins in neuroblastoma cells that are phosphorylated on tyrosine in response to GDNF. The phosphorylated proteins include focal adhesion kinase (FAK), paxillin and Crk-associated substrate, p130Cas, all of which are known to be associated with focal adhesions. Of these, paxillin and p130Cas interacted with Crk proteins in GDNF-treated neuroblastoma cells. GDNF also induced reorganization of the actin cytoskelton. Tyrosine phosphorylation of FAK, paxillin and p130Cas was inhibited by cytochalasin D or two specific inhibitors of phosphatidylinositol-3' kinase (PI-3' kinase), wortmannin and LY294002, indicating that their tyrosine phosphorylation depends on the formation of actin stress fiber and activation of PI-3' kinase. In addition, phosphorylation of FAK but not of paxillin and p130Cas was markedly impaired by the Clostridium botulinum C3 exoenzyme that specifically ADP-ribosylates and inactivates Rho. These results suggested the presence of Rho-dependent and -independent signaling pathways downstream of PI-3' kinase that mediate tyrosine phosphorylation of FAK, paxillin and p130Cas through Ret kinase.

Detection and sequence analysis of borna disease virus p24 RNA from peripheral blood mononuclear cells of patients with mood disorders or schizophrenia and of blood donors

Borna disease virus (BDV) p24 RNA was detected in the peripheral blood mononuclear cells (PBMCs) of psychiatric patients and blood donors by nested reverse transcriptase PCR (RT-PCR). The prevalences of BDV p24 RNA in patients with mood disorders (4%) and schizophrenia (4%) were not significantly different from that in blood donors (2%). This finding was inconsistent with previous reports that showed either a high prevalence or absence of BDV p24 RNA in patients with psychiatric disorders. The differences in BDV p24 RNA prevalence in these studies may be due to differences in the criteria for positivity, the number of PBMCs used for RNA extraction, or the amount of RNA tested for nested RT-PCR or to laboratory contamination. Sequence analysis of BDV p24 RNA from the PBMCs of patients and blood donors showed a high nucleotide sequence conservation but definite nucleotide mutations compared with horse BDV p24 RNA sequences. In comparison with human BDV p24 RNA sequences previously reported from Japan and Germany, there were several positions with silent nucleotide mutations among these clones.

[Spontaneous resolution of idiopathic spinal subdural hematoma: case report]

A 32-year-old female presented with about a week's history of dull pain in the head and neck pain. On the day of admission, she experienced a sudden onset of severe pain, extending from the occipital to the lower back region and hypesthesia and paresthesia of the right C8-Th3 dermatome. On admission, she was alert but there was a band of hypesthesia and paresthesia at the level of C8-Th3. Cervical X-ray, computed tomography scan (CT) and magnetic resonance images (MRI) of the head revealed no definite abnormalities. The peripheral blood picture was normal, and the bleeding and clotting times were in the normal range. The cerebrospinal fluid (CSF) was bloody and the CSF pressure was 220 mm H2O. An emergent 4-vessel intracranial angiography disclosed no abnormal findings. MRI and myelography revealed an intradural extramedullary lesion extending from the Th2 to the Th5 levels, ventral to the spinal cord. A T1-weighted MR image showed iso-low intensity and a T2-weighted MR image showed low intensity at these lesions. Spinal angiography revealed no abnormal vessels. In one month, spinal compression cleared gradually without surgery and her clinical symptoms disappeared about 40 days after admission. Spontaneous spinal subdural hematoma is uncommon and only 28 cases have been reported. 15 cases have been treated with surgical procedure, but spinal compression cleared spontaneously in this case. This spontaneous recovery is such a rare event that only 3 such cases have been reported in the literature. However, with the prevailing MRI, this disease will be detected more frequently in the future.

Characterization of a calcium-dependent protein kinase of tobacco leaves that is associated with the plasma membrane and is inducible by sucrose

The plasma membrane fraction from leaves of tobacco contains a 54-kDa protein with autophosphorylation activity, and the level of this protein increases after feeding of leaves with sucrose [Ohto and Nakamura (1995) Plant Physiol. 109: 973]. The 54-kDa autophosphorylation protein could not be released from the plasma membrane by treatment with salt or alkali but could be efficiently solubilized by 1% sodium deoxycholate (NaDOC). Ion-exchange chromatography of the NaDOC-solubilized proteins in the presence of octylglucoside separated the 54-kDa autophosphorylation protein into three peaks. The autophosphorylation activity of the 54-kDa protein in peaks I and II increased after feeding of leaves with sucrose. The 54-kDa protein in the peak II fraction was enriched about 125-fold starting from the microsomal membrane fraction. The 54-kDa protein in this fraction phosphorylated histone IIIS in a calcium-dependent manner and cross-reacted with an antibody against a calcium-dependent protein kinase (CDPK) of Arabidopsis thaliana. These results suggest that the 54-kDa protein in the peak II fraction is a novel isoform of CDPK which is associated with the plasma membrane and is inducible by sucrose.

Detection of a novel nonsense mutation of the MEN1 gene in a familial multiple endocrine neoplasia type 1 patient and its screening in the family members

We identified a novel nonsense mutation(R29X) of the MEN1 gene in a familial multiple endocrine neoplasia type 1 (MEN1) patient. Molecular analysis of the MEN1 gene was performed in the family members by a restriction digestion method. The same mutation pattern was seen in both the proband's younger brother and cousin diagnosed as MEN1, and was also observed in the son of the cousin who showed signs of normal levels of serum PTH associated with mild hypercalcemia and hypophosphatemia. These findings suggest that mutation analysis of the MEN1 gene is very useful in identifying the subclinical state of MEN1 as well as clinical MEN1.

Inhibitory effects of rebamipide on ENNG-induced duodenal carcinogenesis in mice: a possible strategy for chemoprevention of gastrointestinal cancers

Rebamipide is a potent antioxidative agent; it increases gastric mucosal PGE2 production and thus protects the gastric mucosa. We hypothesized that the mechanisms of ulcer formation could be extended to carcinogenesis and that an increase in gastric mucosal protection may result in a decrease in gastric carcinogenesis. Therefore, we assessed the inhibitory effects of rebamipide on N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) -induced carcinogenesis in mice. The percentage of tumor-bearing mice in three treatment groups--ENNG + rebamipide 20 mg, ENNG + rebamipide 50 mg, and ENNG alone--was 55%, 42%, and 67%, respectively. The incidence of tumorigenesis tended to decrease with increasing doses of rebamipide. The difference between ENNG + rebamipide 50 mg and ENNG alone was statistically significant (P < 0.05). These results suggest that rebamipide may strengthen the host defense mechanisms related to carcinogenesis in the digestive tract.

The gene structure and organization of mouse PG-Lb, a small chondroitin/dermatan sulphate proteoglycan

PG-Lb was originally characterized as a small chondroitin/dermatan sulphate proteoglycan expressed preferentially in the zones of flattened chondrocytes in developing chick limb cartilage. The occurrence of this proteoglycan in mammalian cartilage has been shown by the isolation of a cDNA clone from mouse cartilage cDNA library [Kurita, Shinomura,Ujita, Zako, Kida, Iwata and Kimata (1996) Biochem. J. 318, 909-914]. To understand the regulation mechanisms for such a unique expression, we have investigated a genomic DNA structure of the PG-Lb gene. The gene is composed of seven exons and six introns spanning more than 50 kb. The leucine-rich repeats are encoded from exon V to exon VII. The transcription initiation site has been determined by rapid amplification of the cDNA ends ('5'-RACE'). The possible TATA box was detected about 90 bp upstream of the adenosine residue that was numbered as position +1. Further analyses of 1.5 kb of the 5' flanking region and 2.2 kb of the first intron have revealed several potential binding motifs for transcription factors such as Sox 5 and 9. The presence of those sequences in the PG-Lb gene was discussed in relation to the unique expression of this proteoglycan. The chromosomal localization of the murine PG-Lb gene was determined to be on the mouse chromosome 10 by the fluorescence-in-situ-hybridization ('FISH') method.

Atrial septal displacement for repair of anomalous pulmonary venous return into the right atrium

BACKGROUND

In the repair of anomalous connection of the pulmonary veins to the right atrium, the use of a baffle of pericardium to divert the pulmonary venous blood into the left atrium could cause pulmonary venous obstruction as a result of thickening of the pericardial patch. Anomalous pulmonary venous drainage to the right atrium caused by malposition of the atrial septum primum can be repaired by displacing the shifted septum primum to the normal position.

METHODS

In 5 patients with total (n=2) or partial (n=3) anomalous pulmonary venous drainage into the right atrium, the septum primum was shifted toward the left atrium and the pulmonary veins drained into the anatomic right atrium despite their normal connection with the posterior wall of the left atrium. This method consisted of incision of the posterior edge of the atrial septum primum and displacement of the incised atrial septum between the anomalous pulmonary veins and both venae cavae. No patch was used.

RESULTS

Postoperative echocardiography showed a wide pathway from the pulmonary veins to the left atrium with no stenotic portions. No atrial arrhythmias occurred after the operation.

CONCLUSIONS

This technique may be advantageous because it allows for future growth of the route of the pulmonary venous pathway and avoids postoperative supraventricular arrhythmias.

Alpha1-syntrophin has distinct binding sites for actin and calmodulin

Overlay and co-sedimentation assays using recombinant alpha1-syntrophin proteins revealed that two regions of alpha1-syntrophin, i.e. aa 274-315 and 449-505, contain high-affinity binding sites for F-actin (Kd 0.16-0.45 microM), although only a single high-affinity site (Kd 0.35 microM) was detected in the recombinant full-length syntrophin. We also found that actomyosin fractions prepared from both cardiac and skeletal muscle contain proteins recognized by anti-syntrophin antibody. These data suggest a novel role for syntrophin as an actin binding protein, which may be important for the function of the dystrophin-glycoprotein complex or for other cell functions. We also found that alpha1-syntrophin binds calmodulin at two distinct sites with high (Kd 15 nM) and low (Kd 0.3 microM) affinity.

Increased expression of proliferating cell nuclear antigen in autoimmune hepatitis in a patient with raised serum concentration of CA19-9

A 52 year old woman had autoimmune hepatitis and an increased concentration of serum carbohydrate antigen 19-9 (CA19-9). The origin of the raised CA19-9 was studied using immunohistochemistry. Liver biopsy section showed chronic active hepatitis with large numbers of proliferated bile ductules. Immunohistochemical analysis revealed that the proliferated bile ductule cells were positive for proliferating cell nuclear antigen (PCNA) and for CA19-9. It is speculated that the raised serum CA19-9 concentration was derived from proliferated bile ductule cells and these cells, which are positive for PCNA, may be able to produce high concentrations of CA19-9.